Charles a



(No Model.)

C. A. HITCHCOCK.

TELEPHONE TRANSMITTER.

No. 399,666. Patented Mar. 19, 1889.

HMT

if fem/* w UNITED STATES PATENT OFFICE.

CHARLES A. HITCHCOCK, OF NORTH EAST, PENNSYLVANIA, ASSIGNOR OF TVO-THIRDS TO SAMUEL A. DAVENPORT AND WILLIAM BURNLEY.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent N0. 399,666, dated. March 19,1 1889.

Application led February l2, 18871 Serial No. 227,404:- (No model.) Y

To all whom it may concern.'

Be it known that I, CHARLES A. HITCH- COCK, a citizen of the United States, residing at North East, in the county of Erie and State of Pennsylvania, have invented new and useful Improvements in Telephone Transmitters, of Which the following is a specification.

This invention relates to the type of telephone-transmitters shown in the patents of IO William Burnley, dated November 30, 1886, No. 353,536, and April 12, 1887, No. 361,047, and in an application of the same inventor filed December 9, 1886, Serial No. 221,132.

The object of my invention is to provide a I5 transmitter box or casing that shall be capable of adjustment at different angles relatively to the plane of the horizon, and shall have means for adjusting and holding it at the desired angle. To att-ain such end the box 2O or casing of the transmitter is hung or pivoted to a support upon which it can be swung, in order to cause a rolling or sliding electrode placed on an inclined stationary platform to bear with more or less pressure against the diaphragm electrode, and thus obtain the proper adjustment of the electrodes in accordance with the requirements of the case. The swinging or pivoted transmitter-box is adjusted by a device mounted on the support for said box, and this device serves as a stop to hold the transmitter-box at different angles in relation to its support.

The invention briey outlined in the foregoing statement Will be hereinafter more fully described, and then set forth in the claim.

In the accompanying drawings, Figure 1 is a front vieW of my transmitter, showing the manner of supporting and adjusting the same. Fig. 2 represents the transmitter-casing with its door opened to show the electrodes, induction-coil, and other appendages and battery connections. Fig. 3 is a vertical section of the transmitter and its supporting and ad justing devices. Fig, 4 is a detail view of one of the rests for the permanent inclined plate which supports the loose electrode. Fig. 5 represents a modilication of my invention.

The reference-numeral 1 designates the box or casing which contains or receives the diaphragm, induction-coil, and tension-regu- 5o lating device for the electric current. The front of this box is formed by a hinged door,

2, to which is applied a mouth-piece, 3, which serves to concentrate sound-Waves upon a diaphragm or vibrating plate, 3, placed in rear of said mouth-piece. This diaphragm may be made of any suitable material, but prefer-- ably it is of Wood. At the sides of the door are arranged vertical strips 4t, which serve as rests or supports for a stationary inclined 6o plate, 5. An inclined groove or slot, 6, is made in each strip, and the ends of the plate 5 are slipped into said grooves, so as to hold the same firmly in an inclined position. The strip with its groove is clearly shown in Fin'. 4.

To the diaphragm 3 is applied a block of rubber or Wood, 7, to Which is cemented or otherwise applied a carbon plate or pencil, 8, which constitutes What is termed the dia- 7o phragm-electrode. The latter may extend entirely across the diaphragm in a so-called multiple-contact transmitter, but When only a pair of electrodes are present in the transmitter a carbon plate or boss at the mid- 7 5 dle of the diaphragm Will be suicient. In the instrumentrepresented in Fig. 2 a series of independent carbon pencils, 9, are placed in axial line with each other upon the inclined stationary plate 5, and these pencils make contact with a continuous pencil, 8, extending across the diaphragm. Such disposition of electrodes forms no part of the present invention, it being shown in the application of Villiain Burnley, filed December 9, 1886, Serial No. 221,132. The electrodes shown are tree to roll upon the inclined plane; but they may also be made to slide in the manner indicated in Patent No. 353,536, dated November 30, 1886. 9o

The transmitter-box 1 is shown in the present instance as containing the electrical appliances shown in the patent of Wm. Burnley, dated April 12,1887,No. 361,047. These consist of a compound induction-coil, 12, which is connected with a condenser, 13, at the back of the casing 1. The circuit and battery connections and other old appliances necessary to'the working of the transmitter need not herein be referred to. It is sufficient to say that the local battery-circuit 16 includes the carbon electrodes, inclined plane, and primary of the induction-coil, while the secondary of the latter is connected with the condenser andthe line and ground wires 17 and 18. The novel features of the present invention, so far as the detailed description has gone, are the inclined stationary plate and means for holding the same. I will now proceed to describe what constitutes the invention or the devices which enable me to accomplish the results heretofore only attained by an adjustable inclined plate, as in the patent and application of Villiam Burnley, above referred to.

On a suitable back plate or wall, 19, are mounted two horizontal bars, 20, which have their outer ends provided with openings for the passage of a transverse rod or wire, 21, that bridges the space between said bars. To the top of the transmitterebox are secured eyes 22, through which passes the wire or rod 21, as is clearly seen in Fig. '1. A bar 221,10-

` cated beneath the transmitter-box, extends l from the back plate or support, 19, and it has shown in Fig. 3.

a threaded boss, 2211through which passes a set-screw, 23. This screw bears against the front side of a projectioni, depending from the bottom of the transmitter-box, asis clearly It is evident that by properly turning said screw the transmitter-box is swung bodily upon the wire 21, the latter passing l loosely through the eyes 22 on the boX. Inother'words, by turning the screw the bottom of the box is moved backward or forward,

according to the change of position of the transmitter-box, and consequently such loose electrode can be adjusted to properly perform its work, according to the state of the circuit, the strength of current, or other conditions which render the adjustment of the electrodes necessary to produce sensitive action and perfect transmission.

In Fig. 5 I have shown acurrent-regulating device for a telephone-transmitter,which comprises a diaphragm, a carbon plate, 30, secured to the same and extending entirely across it. Two loose rolling or sliding electrodes, 31, restupon two permanent inclined plates, 32, which are arranged one above the other or located at different altitudes, as shown. Both inclined plates are connected by wires 33 with one pole of a local battery, and a wire, 34,

from the carbon plate 32 goes to an inductioncoil.

I desire it to be understood that the construction speciied may be varied in many of ihe details without departing from the spiritof my invention.

Having thus described my invention, what I claim is- In a telephone-transmitter, the combination of the supporting-arms, the transverse wire orl transmitter-box, and a horizontal bar having a set-screw for adjusting the transmitter-boxl and holding it at different angles relatively to the plane of the horizon, as and for the purpose herein set forth.

In testimony whereof I affix my signature in' presence of two witnesses.

CHARLES A. HITCHCOCK.

Vitnesses:

W. J. HUMPHREY, D. D. Loor. 

